The invention relates to a regulating device for the linear regulation of an actuating element which is connected for movement to a gear drive, in particular a ball spindle drive for the conversion of a rotational movement into a linear movement, whereby the rotational movement can be transferred to the spindle drive through a gear unit by at least one motor.
This type of regulating device is known from DE 200 18 569. The known regulating device is used for regulating a shut-off element as an actuating element in a blowout preventer (BOP), whereby a connection channel in the BOP is closed by the shut-off element. The shut-off element is connected for movement with a ball spindle drive. Through this ball spindle drive, a rotational movement produced by a motor is converted into a linear movement for the regulation of the actuating element. In addition, another gear unit, which in DE 200 18 561 is formed by a worm drive, is arranged between the motor and the ball spindle drive.
This regulating device, in particular through the application of the worm drive, is characterized by a self-locking feature and can also otherwise be usefully employed and exhibits substantial advantages compared to other regulating devices without worm drives However, normally the efficiency is limited to less than 50% and the self-locking feature is also generally only available with a high transmission ratio. In addition, with worm drives relatively high axial forces sometimes occur.
With regard to the regulating device in DE 200 18 561, the object of the invention is the improvement of this type of regulating device such that with a simple and compact design an increase in the efficiency for the reduction of the dissipation is possible and also, in particular, high axial forces can be avoided.